Sync Start for external Synth

Hi,
I am trying to rebuild the “Sync Latch” functionality from my MIDI PAL (this is also known as “Mungo Sync”)
I guess it must be a combination of a MIDI LFO (external synced, Square) and a Transformer which transforms from a Note On/Off (as one example) to Start/Stop/Continue.
Anyone with success in that topic?